Apparatus for refrigeration



March 18, 1930. c. E. MoLEswoRTH Er'AL 1,750,763

APPARATUS FOR REFRIGERATION Filed Sept.. l2, 1927 JOHN Dl/.OMAN

C.6.ZO/rE/ T INVENTORS Patented Mar. 18, 193i) i UNITED y STATES PATENToFElcE C'LYDE E. HOLESWORTH, JOHN DUDMAN, AND CARL G. ZOXELT, OFSEATTLE, WASHINGTON APPARATUS PQR REFBIGERATON Application led September12, 1927. Serial No. 219,028.

This invention relates to refrigerating systems and more particularly torefrigerators of that class using a liquefied gas, such as anhydrousammonia, or any other pre-cooled liquid, as the refrigerant; it beingthe principal object of the present invention to provide a practical andeconomical refrigerating system, especially for mercantileestablishments and private home use, but suit- V ableyalso for otheruses, which employs no pumps, compressors, motors, or the like, in itsoperation and which automatically miamtains a certain predeterminedtemperature within the refrigerated area. More specifically, 'the objectof the present v invention resides in the provision of a refrigeratingsystem using a volatile, liquid refrigerant, as above stated, which maybemaintained indefinitely in'its liquefied state by proper insulation ofits container, with an expansion coillocated in the area to berefrigerated, and so connected with the container as to be supplied withthe refrigerant by gravity fiow and only in accordance with theabsorption of heat from the refrigerated area so as'to therebyautomatically maintain a predetermined refrigerating temperature.

It is also an object of the invention to provide means Vwhereby thecirculation of air 80 within the refrigerated area and about theexpansion coils may be regulated as a means of determining thetemperature within the refrigerated area and to insure its being evenlycooled.

Another object/ of the invention resides in the provision of means forretaining the expanded gas. l

Other objects of the invention residey in the various details ofconstruction and particularly in the combination of parts, aswillhereinafter be described. u i

In accomplishing the various objects, we have provided the improveddetails of -con-A struction, the preferred forms of which areillustrated in the accompanying drawings, wherein- Figure 1 is avertical section taken transversely of a refrigerating system embodiedby the present invention.

. the air within the refrigerating chamber from Figure 2 is a horizontalsection taken substantiallyA on the line 2--2 in Figure 1.

Referring more in detail to the several views of the drawings- 1designates, in its entirety, the Iefrigera- 55 tor body, or housing,which may be of a type and size convenient for mercantile or forhousehold use, or may be made in .larger sizes for railway` car or othercommercial purposes. In its preferred form for domestic 50 use, it wouldbe of box-like form with its walls well insulated in the well-known, orany other suitable manner, so that its inside temperatures would beunaffected by temperatures outside. Within the top of the 5 refrigeratorthere is provided a compartment 2 within which a tank 3, or receptacle,containing the refrigerant 4, is located. Ac cess to this compartmentmay be had through a top opening 5 in the refrigerator within which acover, or wall section, 6, is tightly and removably fitted, and accessto the tank is provided for through a top opening within which a plug 3ais threaded.

Below the compartment 2, and separated therefrom by an insulating wall7, is the refrigerating chamber 8 and located within the top of thischamber is a series of expansion, A or cooling, coils 9 consisting ofrelatively small pipes which, at their upper ends, conneet with a feedpipe 10 leading downwardly through an opening 7 in the partition wall 7from the base of the tank 3 so that the liquid refrigerant -may flow bygravity from the tank into the coils. Preferably, these coils arearranged so as to enclose a rectangu! lar area, as shown in Figure 2,within which a frame structure l2 is supported 'for containing aplurality of trays 13 which may be slid into and from the same andwithin which water, or articles of food, may be placed for quickfreezing. This freezing zone 8iis enclosed by a sheet metal housing 14which is for the purpose of preventing coming into direct contact withthe expansion coils with a resultant lowering of the temperature to apoint far below that revquired or desired; also, for preventingexcessive deposit of moisture in the form of 10 frost on the coils whichwould ultimately insulate them to a certain extent and also to preventvapors or odors, from food or articles in the re rigerating chamber 8from being absorbedby food products being prepared in the trays 13. Thewalls of the housing 14 are laced close to the coils 9 and this leaves asu stantial space between them and the side and top walls of therefrigerating chamber for the circulation of air.

As a means of controlling the circulation of air within therefrigerating chamber as a means of temperature control and also toei'ect an even temperature throughout the chamber, we have fixed aperforated, sheet metal plate 15 in horizontal position and slightlyspaced below the bottom lwall 14 of the housing 14 to provide an aircirculating space, 16 between the two., The side edges of the late 15terminate short ofthe side Walls of) the refrigerating chamber and theseedges are adapted to be bent downwardly, as at 15 in Figure `1, so as toprovide air pas-A sages 17 of widths or areas which, by experiment, arefound to be correct for maintaining a certain predetermined temperaturewithin the cooling area in the lower portion of the refrigerator; thisdegree of-temperature of course being dependent on the temperature madepossible by the expansion coils and the rate of air circulationabout theexpansion coils as determined by the area of the passages 17. Also,extending upwardly from the side edges of the plate 15 in parallelrelation to the side and top Walls of the refrigerating chamber and alsospaced therefrom and from the side and top' walls of the housing 14, areplates, or deectors, 20, which terminate in spaced relation at the topof the chamber. These walls provide that air circulating upwardly withinthe refrigerating chamber will, after passing through the passages 17.cont-inne upwardly along the sides and-top of the chamber walls and willthen return downwardly over the topand side walls of the housing 14 andwill be cooled by contact therewith and then distributed through theperforations of the plate 15 downwardly into the chamber, as indicatedby the arrows in Figure l. This arrangement of baille plates retards theair circulation tc'rthat extent necessary for insuring a desiredtemperature with- 1n the refrigerating chamber and also effectsan evendistribution of the cooled air to all parts of the chamber.

It will be mentioned here thatlaecessto the refrigerating chamber may behad through an opening 21 at the front of the refrigerator within whicha door 22 is fitted, as indicated in Figure 2, and that suitablesl1elves,.as at 23, may be provided in the chamber; however, the details4of construction of the housing itself and arrangement and number ofdoors used is not material to this invention so long.

serves as a trap for preventing the refrigerant from flowing into thefilling pipe and wasting; it being apparent that gas confined in theupper portion of the pipe 25 will causethe liquid refrigerant t'o bebacked u and retained back of the trap. Leading fiom the top of the tank3 is a pipe 30 through which expanded gas may escape from tank 3 and bedirected into a retaining tank 31, presently described in detail.

Assuming the device to be so constructed, its operation would be asfollows:

First, the tank 3 is filled to a suitable depth with a liquefied gas,such as anhydrous ammonia, or any other suitable pre-cooled liquid; thisbeing admitted to the tank through pipe 25, the expansion coils 9 and10. Except at times when the tankis bein charged, the valve 26 istightly closedin order to pre-l vent pressure within the tank fromforcing the liquid out through pipe 25. Air within the housing 14, orfreezing zone 8, is excessively cooled due to its intlmate relation withthe coils 9. Air circulating within the refrigerating chamber 8 comesinto contact with the walls of housin 14 which encloses the expansioncoils 9 and reezinvr zone 8 and heat is ex` tracted froml this air hyreason of the lower tem erature within the housing.

Hleat thus transmitted from the air to the vcoils transforms some of thevolatile refrig? erant into gas which bubbles up through the pipe 10into tank 3 and passes oli' through pipe 30 vinto tank 31. The rate ofthis transformation of the refrigerant from liquid to j gas is, ofcourse, controlled by the amount lof heat that can be extracted from theair and is dependent to a great extent on the rate of circulation ofairin contact with the housing 14. In the present instance, the rate ofcirculation and resultant temperature is con-l trolled by a properdetermination of the area of the passages 17. It is readily understoodplaced within the refrigerating chamber for cooling, and this heatcarried by the a1r 1s ultimately taken up by the coils 9 and 4absorbedin the gasifying of some of the refrigerant; the rate of which is inproportion to the amount of heat absorbed. It is further understoodthat, considering the tank 3 to be perfectly insulated, the refrigerantthereln will remain in its liquefied state indefinitely `that heat willbe extracted from any article and it willbe suppned to the expansioncoils only as required to replace that given up in the form of gas dueto absorption of heat. lIt is apparent then, that the delivery ofrefrigerant to the coils is automatically controlled and is more, or'less, inproportion to the amount of heat absorbed by the coils fromobjects placed for cooling within the refrigerating chamber. If no heatcan be extracted, no refrigerant. is used.

For the purpose of retaining the gas given olf from the containerthrough pipe 30; we have provided thetank 31 which is partially filledwith water or other absorbent. The pipe 30 o ens within the tank closeto its base so that the gas from the pipe is caused to bubble into,theabsorbent which retains it.

In the present illustration, a branch pipe l 35 connects with the pipe30 above the tank 31 and this leads through a 3-way valve 36 into a pipe37which opens into the top of the tank. Normally the valve 36 isadjusted so as to close passage through pipe 35 and to I connect pipe 37with atmosphere.

When it is desired to empty the tank 31 of its contents, the valve 36 isadjusted so as to provide direct connection from pipe 3() to the top ofthe tank. Then the gas becomes confined under pressure in tank 3 and isreleased into the upper portion -of tank 31 and is utilized to expel theliquid from tank 31 through a discharge pipe 42 which leads upwardlyfrom near the base' of the tank and through the top thereof. This latterpipe is provided with a water `level gauge 43 by means of which internalwater level may be determined, and also is equipped with a valve 44 anda connection 45 to which a conduit, not shown, may be attached forfilling or emptying the tank.

While we have described this system as arranged for domestic use, it isto be understood that thev same system can readily be adapted tocommercial purposes, such as in railway cars, ships, refrigerating and.cold storage plants,l and we do not wish to confine itsscope only tothe system shown.

Having thus described our invention, whatv weclaim as new therein anddesire to secure by Letters Patent, is:

1. A device of the character described comprising an-"insulated housingproviding an- Insulated compartment in the to portion thereof andarefrigerating cham er below saidcom Vartment, an insulated tank diS-posed wit in the top compartment for containinga supply of liquidrefrigerant, a vent pipe leading. from the top of said tank, an exansion coil located within the top of the j re rigerating chamber havinga pipe connection with the base ofthe refrigerant container throughwhich the coil may be sup-` plied-by gravity flow and through which gasmay be vented from vthe coils, a fillingdpipe, connected with thekbaseof the coil tended upwardly to a point above the refrigerantcontainer and a trap in said filling pipe adjacent its connectionwiththe coil for preventing outward passage of the refrigerant.

2. A refrigeratbr of the character described comprising a housingproviding an insulated compartment, in t e to vportion thereof and arefrigerating cham er below said compartment, a closed container disosedwithin the top compartment for' coning a,volatile liquid refrigerant,said container having a vent pipe leading from the top thereof, anexpansion coil located within the top of the refrigerating chamberhaving a pipe connection at its top end with the base of the refrigerantcontainer through which the coil may be supplied by gravity flow andthrough which gas may be vented from the coils, a filling pipe connectedwith the lower end of said coil having a trap therein adjacent itsconnection with the coil for preventing outflow of refrigerant, ahousing inclosingthe coil in spaced relation from the walls of -therefilgerating chamber providing an interior freezing zone'and airdeflect- 4ing plates suitably disposed within the re an expansion coilhaving a pipe connection with the container through which the coil maybe supplied withrefrigerant by gravity flow and through which gas isvented from the coils into the container, of a closed tank for a gasabsorbing liquid, a gas discharge pipe leading from the vent pipeconnection of the refrigerant container into the said tank to a pointbelow the liquid level therein, a pipe connection between the said gasdischarge pipe and the top vof the tank, a valve in said pipe connectionwhereby direct communication may be made between the gas vdischarge pipeand the top of thetank, or with atmosphere, and a liquid discharge pipeleadinor from near the base of the tank through which the liquid may beforced by a pressure of gas delivered from the gas discharge pipe intothe to of the tank.

Signed at Seattle, ashington, this 1st day of September, 1927. v

CLYDE E. MOLESWORTH.

JOHN DUDMAN.

CARL G. ZOKELT.

